Thermostat.



J. BOEKEL.

THERMOSTA'I.

APPLICATION FILED DEG. 1, 1913.

Patented Sept. 15, 1914.

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THE NORRIS FLIBR-v at), HHOTO-LITH WASHINGTON, D. L.

" tau ai "l "Twat Specification or Application filed December i a Patented Sea.

To all whom it may concern Be it known that l, JuLIUs Bonnnn, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful improvements in Thermostats, of which the following is a specification.

This invention is inpro ement on the subject matter of my Letters Patent No. 1,094,362 and relates espe ially to the circuit closing float employed Hitherto,

tilQfQlil. so far as applicant is aware, such floats have been made of material, preferably steel, which is subject to superficial oxidation, greatly increasing friction the float ascends and descends with the mercury or other expansible liquid. The present inven tion remedies this defect by making the body of said float of non-oaidizable material, suitable to such use, said body having a central bore, wherein is a longitudinal metallic rod haying contacts at its ends, the lower contact, as in such application, being adapted to penerate the more or less oXidized surface of mercury below it and remaining permanently immersed therein, and the upper contact serving to close an electric circuit when the float is carried by the mercury up to a certain point.

In the accompanying drawings: Figure 1 represents a vertical central section of a thermostat embodying my invention, th lower part of the mercury tube or receptacle being broken away, the plunger and the adjusting and set screws being left in elvations, but the float being sectioned; 2 represents in elevation the float body and its internal rod arranged side by side; and Fig. 3 represents a cross-section through the middle part of the same.

The mercury-tube or reservoir 1 is of usual construction, externally screw-threaded at the top to turn into screw-tapped recess 7 of an insulating block 6, constituting the body of the thermostat. Below said screwthreads, there is a collar 2 on said tube, having a radial stud or screw-post 3, which receives at 4c a wire a held by set-screw 5.

Block or body 6 has a vertical guide-passa 'e for tie inercury-adjusting plunger 12, of insu at 1 material locked at any point by screw 11 terrains; through the side of said ne latter has on its top a cylindrial block 19, externally screw-threaded to an internally screw-threaded elecconducting casing 18 and said. post d body ha ing an internal, vertical, cylinal bore 20 extending down through them .n annular shoulder 06 near the bottom or he latter surrounding a central hole 3? which connects the said bore with the uuper end of the mercury tube 1. l

1 adjusting screw 18 works down engagement with a contact 34, carried by the upper end of the float 32 hereinafter de scribed. ii longer piirforin or needle-form 1,3 on the lower end of said at is -ently immersed in the mercury and course penetrates the oxidized surface thereof, also passing through hole 37, in which it guided. The upper end of said body has an annular groove 38 formed there in for receiving any excess of mercury carried up by said float.

A lateral arm 21, integral with casino; 18, receives transversely a wire 6 held by a set screw 23. The contacts are preferably of platinum.

The parts hereinbefore described are substantially identical in construction, combination and operation with the corresponding ones of my previous application before men tioned, and are set forth merely to make clearer the action of the improved float, hereinafter explained, in cooperation with said parts.

My improved float consists of a cylindrical float body A of the material known a bakelite or other material not subject to oxidation. Said float-body is cylindrical in form and [its the bore 20, as closely as is consistent with the necessary freedom of working; of said float up and down tierein. This body is preferably provided with convex upper end thereof and ids with contacts 3-3 and a some mercury en work up l the side of the r and the wall of the bore v oxidircable film which dation of "he contiguous said float well, if the super- ;"t said consist of material stitch. action. This will be in said floats a material ize; but it is of course material should be of descend with certainty h fitting it as closely as is the electrical conduciioat should be unimrod l3 answers both of requirements, its mass being sufficient 1 .e ner, and the circuit when its contact caches contact 25 being from wire a th rd ruiry tube 1, mercury 22, concontacts at and 25, screw 18, d arm 21 to wire 6. The material of the float body A will not "iactorily eflicient and durable unless esist tie action of liquids mercural a certain amount of heat, main 7 its form, firmness of texture and smootlmess of surface, considerations which make i'ulcanized rubber and most vegetable ii er inferior for use to some specially adapted materials and compositions, of which bakelite is found by practical tests to be among the best. I do not wish, however, to confine iyself to any single materials or number of materials, since any substance may c used whic i will not oxidize and which is capable of l'lHlllllX-Bdfid and continu ous use in a here or passage and in a therimistat rmntrolled by cxpansible liquid as J. Jr time a bore fitting the float in which the latter moves.

fr circuit-closing float for a thermostat consisting of a body of non-oxidiizable material having a longitudinal central bore :1 ml a metallic rod fitted into said bore and pro vided with contacts on its ends extending beyond said body, in combi ation with a ixed part having a bore fitting said body, in which here said float moves up and down, a mercury receptacle below said bore which communicates with the latter by means of a hole of less diameter than said bore, and. devices adapted to make circuit through said contacts and rod, the lower contact of said float being of sullicient l ngth to extend down through said hole into said receptacle and of suficiently small diameter to penetrate below the surface f the mercury.

3. A float having a non-oxidizable sitirface and provided with a longitudinal interior part of heavier material than that of which it is mainly composed and adapted. to make electrical contact at bot-h ends, in combination with a fixed part having a bore in which said float lllOJGS up ant down, a column of conducting liquid arranged immediately under said bore, means for raising and lowering said float, and conductors adapted to make electrical circuit through said rod, the lower contact of said float being adapted to extend down below said bore and to penetrate below the surface.

i. A float for thermostats consisting of a body of non-oxidizable material adapted to retain its form, texture and smoothness and having a central bore, and a metallic rod titted into said bore and extending through the float at both ends, and having a lower contact sufliciently elongated and of sufficiently reduced diameter to penetrate readily below the surface of mercury, in

combination with a mercury column. arranged below said bore and means for preventing the descent of the body of the float into the mercury.

5. A float for thermostats consisting of a bakelite body, a steel rod within the same and contacts set into the ends of said rod the lower contact being of considerable length and reduced diameter for the purpose set forth.

6. A float for thermostats consisting of a non-oxidizable body having a bore through it, a metallic rod fitting said bore and a contact of less diameter set into one end of said rod and adapted to penetrate readily the surface of the liquid, the other end of said rod being also provided with a contact for the purpose set forth.

7 In combination with the mercury column of a thermostat and electric circuit conductors for making circuit through the same, a float rising and falling with said mercury and having a part which penetrates belov the surface of the same so as to be continually in electrical contacttherewith a fixed part having a bore fitting said float, and in Which said float rises and falls, and a relatively fixed contact above said float, the latter consisting of a non-oxidizable body and a metallic rod extending through the 10 same, said rod being provided on its upper end with a contact for coaction with said relatively fixed contact substantially as set forth.

In testimony whereof, I have signed my name to this specification in the presence 1:3 of two subscribing Witnesses.

JULIUS BOEKEL.

Witnesses JOHN H. SGHERER, FREDK. MANGOLD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. G. 

